<mat-toolbar>
  <button mat-icon-button (click)="openSideBar()">
    <mat-icon>menu</mat-icon>
  </button>
  <span>企业协作平台</span>
  <div class="fill-remaining-space"></div>
  <mat-slide-toggle (change)="onSlideToggleChange($event)">切换主题</mat-slide-toggle>
  <a class="header-txt" routerLink="/login">退 出</a>
</mat-toolbar>
